Medication delivery systems are known in the art. As indicated above, medication delivery systems are used to deliver pain control medication and other medications intra-operatively, subcutaneously, and percutaneously to a patient after a surgical, or some other medical, procedure.
Conventional medication delivery systems are deficient for one reason or another. For example, U.S. Pat. No. 5,807,075 to Jacobsen et al. discloses a conventional medication delivery system that includes a base housing and a cassette. The base housing of the '075 patent houses electronic components, such as an electric motor, a power source, and an electronic controller, and the cassette of the '075 patent interacts with a supply of the medication to deliver the medication to the patient. This medication delivery system is deficient because the supply of the medication is not integrated into the cassette. That is, the cassette does not house the supply of the medication. Instead, the supply is external to the medication delivery system. This medication delivery system is also deficient because the base housing and the cassette are not properly integrated. As such, the complete medication delivery system, having the base housing and the cassette, cannot be simultaneously sterilized prior to use of the system. Instead, the base housing and the cassette require separate sterilization. Furthermore, because the base housing and the cassette are not integrated, the cassette must be mounted to the base housing which requires additional assembly by a surgeon or some other medical assistant. This additional assembly is time consuming and is often inconvenient for the surgeons and medical assistants.
A further example of a conventional medication delivery system is disclosed in U.S. Pat. No. 4,650,469 to Berg et al. This patent discloses a medication delivery system that includes a control module and a reservoir module removably connected to the control module. The control module includes a pump mechanism, valves, a power source, electronic controls, and the like, and the reservoir module includes a container that supplies the medication to be delivered to the patient. Although the medication delivery system disclosed in the '469 patent connects the control module and the reservoir module, this medication delivery system is deficient in that, once connected, the control module and the reservoir module cannot be simultaneously sterilized. The modules cannot be simultaneously sterilized because, as described at column 11, lines 22–28, one of the valves in the control module closes the fluid connection (the tube 22) between the control module and the reservoir module at all times. That is, the '469 patent does not include a device, such as an actuator, to prevent the valves from closing on this fluid connection. As such, a sterilization fluid, such as ethylene oxide (EtO) gas cannot flow into both the control module and the reservoir module once these modules are connected.
The conventional medication delivery system disclosed in the '469 patent is also deficient because it relies exclusively on a motor and a cam shaft to move the valves from the open position to the closed position when delivering the medication to the patient. This medication delivery system does not incorporate an additional biasing device to ensure that the valves are biased into the closed position if the motor, gear, cam shaft, or power supply fails. Without such an additional biasing device, this system's ability to prevent the inadvertent delivery of the medication to the patient in the event of one of the above failures is compromised. Instead, this medication delivery system relies only on the motor and the cam shaft to allow or to prevent delivery of the medication, and reliance on these two components is insufficient.
Other conventional medication delivery systems are also deficient for a multitude of other reasons. For instance, these conventional systems do not incorporate port assemblies that adequately control the flow of medication throughout the system. In these conventional systems, a single port assembly does not enable various medical fluids to flow into, from, and within the system. Conventional medication delivery systems also do not provide detection systems that adequately determine when a medication delivery system is realizing a blockage in the flow of medication to the patient or that adequately determine when a supply in the medication delivery system has been depleted. The detection systems in the prior art medication delivery systems do not make optimum use of the position of the tubes that carry the medication relative to the position of the electronic controller. Conventional medication delivery systems also do not provide a testing access port that allows manufacturers to confirm operation of the medication delivery system after assembly, and prior to use, of the system. As such, the operation of many prior art medication delivery systems cannot be confirmed prior to shipment to medical professionals for use. Conventional medication delivery systems are also not ideal for carrying. Some prior art systems do not even include a carrying strap. As such, the patient cannot be easily treated outside of a hospital or other medical facility, the patient is prevented from being ambulatory. Other medication delivery systems in the prior art that do include some form of carrying strap do not make carrying convenient because, in these systems, the carrying strap is not conveniently stored in a storage cavity of the system. That is, the carrying strap is not integrated into the system itself for easy access by the patient. The medication delivery systems of the prior art are also not easily controlled. That is, there is not method associated with these systems that effectively controls an amount of the medication to be delivered to the patient. The prior art methods for controlling the amount of medication that is to be delivered to the patient are deficient because these methods require constant attention, require complicated setup and monitoring by the surgeon or other medical professional, and may even risk the health and safety of the patient. Other conventional medication delivery systems do not have electronic controllers, specifically specialized circuitry incorporated into the controller, that adequately prevent too much medication from being delivered to the patient in the event of failure of certain mechanical components. Also, the electronic controllers and circuitry of other conventional medication delivery systems are not suitably designed to maximize the conservation of power and to prevent the entire medication delivery system from being reset by removing and replacing the power source, e.g. a battery.
Due to the deficiencies in conventional medication delivery systems, including those described above, it is desirable to provide a novel medication delivery system that is appropriately integrated for simultaneous sterilization. It is also desirable to provide a novel medication delivery system that overcomes the other deficiencies identified above in the prior art.